401
FXUS65 KBYZ 211840
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1240 PM MDT WED OCT 21 2026
KEY MESSAGES
- WARM AND DRY CONDITIONS THROUGH THURSDAY.
- STORM SYSTEM LATE THURSDAY NIGHT INTO SATURDAY MORNING BRINGS
LOWER ELEVATION RAIN AND MOUNTAIN SNOW; GREATEST TOTALS FORECAST
WEST OF BILLINGS, WITH LITTLE TO NO PRECIPITATION OVER SE
MONTANA.
- ELEVATED FIRE WEATHER CONCERNS SOUTHEAST MONTANA FRIDAY
AFTERNOON-EVENING.
- WINDY CONDITIONS (GUSTS 30-45 MPH) EXPECTED FRIDAY INTO
SATURDAY.
- SEASONAL TEMPERATURES (HIGHS IN THE 50S) AND UNSETTLED
CONDITIONS (20-40% PRECIPITATION CHANCES) SUNDAY THROUGH
WEDNESDAY. UNCERTAINTY IS HIGH FOR THE EXTENDED FORECAST.
DISCUSSION
NEXT 7 DAYS (THRU TUESDAY)...
CONTINUE WITH A WARM AND DRY FORECAST THROUGH THURSDAY NIGHT.
RIDGING ALOFT TODAY SHIFTS TO FASTER SOUTHWEST FLOW ON THURSDAY.
THE ENHANCED DOWNSLOPE FLOW WILL HELP TO BOOST TEMPERATURES WELL
INTO THE 70S, WITH A FEW LOWER 80S NOT OUT OF THE QUESTION OVER SE
MT. RECORD HIGHS ARE POSSIBLE THURSDAY FOR MILES CITY (REC 78) AND
BAKER (REC 71 DUE TO SHORT PERIOD OF RECORD). SOUTH-SOUTHWEST
WINDS WILL ORIENT WITH THE WESTERN VALLEYS THURSDAY AFTERNOON, SO
EXPECT BREEZY TO GUST CONDITIONS (20-35MPH) FOR THE PARADISE
VALLEY AND WESTERN FOOTHILLS, AS WELL AS THE HIGHER TERRAIN.
MODELS STILL ADVERTISING THE MERGER OF AN UPPER LEVEL SYSTEM
MOVING NORTHEAST OUT OF CALIFORNIA, AND A CANADIAN SHORTWAVE OVER
THE AREA FRIDAY INTO EARLY SATURDAY. HOWEVER, THERE HAS BEEN A
GRADUAL CHANGE IN HOW STRONG THIS SYSTEM WILL BE AS IT COMBINES
OVER THE AREA, WITH PRECIPITATION AMOUNTS IN THE LOWER ELEVATIONS
EAST OF THE DIVIDE TRENDING SIGNIFICANTLY DOWNWARD, ESPECIALLY IN
THE DETERMINISTIC MODELS. NBM IS SLOWLY CATCHING UP WITH THIS
DOWNWARD TREND THIS MORNING WHICH IS A RESULT IN ITS LAG FEATURE.
TO HIGHLITE THE CHANGES AND THE UNCERTAINTY THAT HAS BUILT INTO
THE FORECAST OVER THE PAST 24 HOURS, THE PRECIPITATION SPREAD IN
THE NBM MEMBERS FOR BILLINGS RANGE FROM A LOW OF 0.01 INCHES TO A
HIGH OF 1.9 INCHES, WITH THE 50TH PERCENTILE SITTING AT 0.38
INCHES. THIS SHOWS THE LATEST DISTRIBUTION SKEWING TOWARD THE
LOWER END OF THE RANGE IN THE LATEST MODEL RUNS. THE PROBABILITIES
FOR MORE THAN HALF AN INCH OF PRECIPITATION HAVE DECREASED OVER
THE PAST 24 HOURS AS WELL WITH AREAS WEST OF A ROUNDUP TO HARDIN
LINE SHOWING 40-50 PERCENT FROM FRIDAY MORNING THROUGH SATURDAY
MORNING (WAS 60-80%). UPSLOPE WINDS ARE HELPING TO BOOST THE
WESTERN FOOTHILLS TO 60-80% WITH HIGHER VALUES FOR THE MOUNTAINS.
BOTTOM LINE THE TRENDS ARE LOWER FOR AMOUNTS, BUT THE PROBABILITY
OF SEEING PRECIPITATION REMAINS HIGH FOR FRIDAY INTO EARLY
SATURDAY.
THE TRACK OF THE CONTROLLING SYSTEMS HAVE ALSO ADJUSTED TO HAVE
LESS OF A WEST TO EAST MOVEMENT OVERALL, FURTHER REDUCING
PRECIPITATION CHANCES OVER SE MONTANA, AND BRINGING A PERIOD OF
ELEVATED FIRE WEATHER CONCERNS TO THIS AREA FOR FRIDAY AFTERNOON
AND EVENING. SOUTHERLY WINDS WILL GUST 30 TO 40 MPH WITH RH VALUES
DROPPING TO AROUND 20% AND TEMPERATURES NOW TRENDING WARMER THAN
THURSDAY FOR AREAS ALONG AND EAST OF A BROADUS TO BAKER LINE.
RECORD HIGHS ARE POSSIBLE ONCE AGAIN FRIDAY AFTERNOON FOR MILES
CITY (REC 77) AND BAKER (REC 69 DUE TO SHORT PERIOD OF RECORD) AS
THE COLD FRONT LOOKS TO HOLD OFF ACROSS SE MONTANA UNTIL THE
EVENING HOURS FRIDAY.
SNOWFALL AMOUNTS HAVE REMAINED FAIRLY CONSISTENT OVER THE PAST 24
HOURS WITH 4 TO 8 INCHES OVER THE WESTERN MOUNTAINS
(CRAZY/BEARTOOTH/ABSAROKA) AND 2 TO 4 INCHES FOR THE BIGHORN/PRYOR
MOUNTAINS. SNOW LEVELS DROP FROM 10KFT LATE FRI AFTERNOON, TO
UNDER 4KFT BY SATURDAY MORNING. HOWEVER WITH LESS PRECIPITATION
AND PRECIPITATION TAPERING OFF FASTER THE LOWER ELEVATIONS (BELOW
6000FT) ARE LOOKING AT LITTLE TO NO SNOW ACCUMULATION WITH THIS
SYSTEM NOW. HOWEVER THAT DOESN'T MEAN THERE WON'T BE SOME FLAKES
MIXING IN DOWN TO AROUND 4KFT AROUND SUNRISE SATURDAY MORNING AS
PRECIPITATION IS ENDING.
WITH THE SYSTEM CHANGES FOR EARLY IN THE WEEKEND THE EXTENDED
FORECAST HAS TRENDED MORE UNCERTAIN AS WELL. OVERALL A SEASONABLY
COOL PATTERN WITH 20 TO 40% CHANCES FOR PRECIPITATION FROM SUNDAY
AFTERNOON THROUGH WEDNESDAY. ANOTHER UPPER LOW MAY DRIVE UP INTO
THE AREA FROM THE 4 CORNERS LATE SUNDAY INTO MONDAY MAINLY
IMPACTING SE MONTANA, WITH A PACIFIC SYSTEM PUSHING INTO THE
REGION TUESDAY/WEDNESDAY FROM THE WEST. A LOT OF TROPICAL ACTIVITY
GOING ON IN THE PACIFIC WHICH CAN HAVE SIGNIFICANT IMPACTS ON
STORM SYSTEM MOVING INTO OUR AREA, AND EXPECT THE MODELS TO
STRUGGLE IN THE LONGER RANGES AS LONG AS THAT ACTIVITY CONTINUES.
SO, CONSIDER UNCERTAINTY TO BE AT A HIGHER LEVEL THAN USUAL FOR
THE FORECAST BEYOND SATURDAY. CHAMBERS
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD WITH PASSING MID
AND HIGH CLOUDS. THERE IS A LOW CHANCE (15%) OF A FEW SHOWERS OVER
THE WESTERN MOUNTAINS THIS AFTERNOON AND EVENING. THERE IS A LOW
CHANCE (10-30%) FOR FOG TO IMPACT TAF SITES NEAR LOW LYING RIVER
BASINS, INCLUDING KBIL, KSHR, KMLS, AND KBHK, OVERNIGHT.
STP/ARCHER
PRELIMINARY POINT TEMP/POPS
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 045/074 049/068 036/051 031/050 030/051 032/057 034/052
00/U 06/R 80/U 00/U 11/B 21/B 32/W
LVM 041/074 043/058 026/047 025/050 024/054 027/055 026/051
00/U 19/R 90/U 01/U 11/B 23/W 32/J
HDN 039/076 045/072 032/052 027/055 028/055 029/059 028/054
00/U 05/R 80/B 00/U 11/B 11/B 22/W
MLS 044/075 048/074 036/048 030/051 031/051 032/056 032/051
00/U 01/B 40/U 00/U 11/B 11/B 22/W
4BQ 050/078 053/079 037/048 032/051 033/052 034/058 034/053
00/B 00/N 20/U 01/U 11/B 11/B 11/B
BHK 043/079 048/082 032/048 024/049 025/048 026/056 028/052
00/U 00/N 20/N 01/U 22/W 11/B 21/B
SHR 042/076 045/074 031/049 026/054 028/056 029/061 028/055
00/B 01/B 51/N 01/U 11/B 11/B 21/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page